the-tree/mm/hmm.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright 2013 Red Hat Inc.
0004  *
0005  * Authors: Jérôme Glisse <jglisse@redhat.com>
0006  */
0007 /*
0008  * Refer to include/linux/hmm.h for information about heterogeneous memory
0009  * management or HMM for short.
0010  */
0011 #include <linux/pagewalk.h>
0012 #include <linux/hmm.h>
0013 #include <linux/init.h>
0014 #include <linux/rmap.h>
0015 #include <linux/swap.h>
0016 #include <linux/slab.h>
0017 #include <linux/sched.h>
0018 #include <linux/mmzone.h>
0019 #include <linux/pagemap.h>
0020 #include <linux/swapops.h>
0021 #include <linux/hugetlb.h>
0022 #include <linux/memremap.h>
0023 #include <linux/sched/mm.h>
0024 #include <linux/jump_label.h>
0025 #include <linux/dma-mapping.h>
0026 #include <linux/mmu_notifier.h>
0027 #include <linux/memory_hotplug.h>
0028
0029 #include "internal.h"
0030
0031 struct hmm_vma_walk {
0032     struct hmm_range    *range;
0033     unsigned long       last;
0034 };
0035
0036 enum {
0037     HMM_NEED_FAULT = 1 << 0,
0038     HMM_NEED_WRITE_FAULT = 1 << 1,
0039     HMM_NEED_ALL_BITS = HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT,
0040 };
0041
0042 static int hmm_pfns_fill(unsigned long addr, unsigned long end,
0043              struct hmm_range *range, unsigned long cpu_flags)
0044 {
0045     unsigned long i = (addr - range->start) >> PAGE_SHIFT;
0046
0047     for (; addr < end; addr += PAGE_SIZE, i++)
0048         range->hmm_pfns[i] = cpu_flags;
0049     return 0;
0050 }
0051
0052 /*
0053  * hmm_vma_fault() - fault in a range lacking valid pmd or pte(s)
0054  * @addr: range virtual start address (inclusive)
0055  * @end: range virtual end address (exclusive)
0056  * @required_fault: HMM_NEED_* flags
0057  * @walk: mm_walk structure
0058  * Return: -EBUSY after page fault, or page fault error
0059  *
0060  * This function will be called whenever pmd_none() or pte_none() returns true,
0061  * or whenever there is no page directory covering the virtual address range.
0062  */
0063 static int hmm_vma_fault(unsigned long addr, unsigned long end,
0064              unsigned int required_fault, struct mm_walk *walk)
0065 {
0066     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0067     struct vm_area_struct *vma = walk->vma;
0068     unsigned int fault_flags = FAULT_FLAG_REMOTE;
0069
0070     WARN_ON_ONCE(!required_fault);
0071     hmm_vma_walk->last = addr;
0072
0073     if (required_fault & HMM_NEED_WRITE_FAULT) {
0074         if (!(vma->vm_flags & VM_WRITE))
0075             return -EPERM;
0076         fault_flags |= FAULT_FLAG_WRITE;
0077     }
0078
0079     for (; addr < end; addr += PAGE_SIZE)
0080         if (handle_mm_fault(vma, addr, fault_flags, NULL) &
0081             VM_FAULT_ERROR)
0082             return -EFAULT;
0083     return -EBUSY;
0084 }
0085
0086 static unsigned int hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
0087                        unsigned long pfn_req_flags,
0088                        unsigned long cpu_flags)
0089 {
0090     struct hmm_range *range = hmm_vma_walk->range;
0091
0092     /*
0093      * So we not only consider the individual per page request we also
0094      * consider the default flags requested for the range. The API can
0095      * be used 2 ways. The first one where the HMM user coalesces
0096      * multiple page faults into one request and sets flags per pfn for
0097      * those faults. The second one where the HMM user wants to pre-
0098      * fault a range with specific flags. For the latter one it is a
0099      * waste to have the user pre-fill the pfn arrays with a default
0100      * flags value.
0101      */
0102     pfn_req_flags &= range->pfn_flags_mask;
0103     pfn_req_flags |= range->default_flags;
0104
0105     /* We aren't ask to do anything ... */
0106     if (!(pfn_req_flags & HMM_PFN_REQ_FAULT))
0107         return 0;
0108
0109     /* Need to write fault ? */
0110     if ((pfn_req_flags & HMM_PFN_REQ_WRITE) &&
0111         !(cpu_flags & HMM_PFN_WRITE))
0112         return HMM_NEED_FAULT | HMM_NEED_WRITE_FAULT;
0113
0114     /* If CPU page table is not valid then we need to fault */
0115     if (!(cpu_flags & HMM_PFN_VALID))
0116         return HMM_NEED_FAULT;
0117     return 0;
0118 }
0119
0120 static unsigned int
0121 hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk,
0122              const unsigned long hmm_pfns[], unsigned long npages,
0123              unsigned long cpu_flags)
0124 {
0125     struct hmm_range *range = hmm_vma_walk->range;
0126     unsigned int required_fault = 0;
0127     unsigned long i;
0128
0129     /*
0130      * If the default flags do not request to fault pages, and the mask does
0131      * not allow for individual pages to be faulted, then
0132      * hmm_pte_need_fault() will always return 0.
0133      */
0134     if (!((range->default_flags | range->pfn_flags_mask) &
0135           HMM_PFN_REQ_FAULT))
0136         return 0;
0137
0138     for (i = 0; i < npages; ++i) {
0139         required_fault |= hmm_pte_need_fault(hmm_vma_walk, hmm_pfns[i],
0140                              cpu_flags);
0141         if (required_fault == HMM_NEED_ALL_BITS)
0142             return required_fault;
0143     }
0144     return required_fault;
0145 }
0146
0147 static int hmm_vma_walk_hole(unsigned long addr, unsigned long end,
0148                  __always_unused int depth, struct mm_walk *walk)
0149 {
0150     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0151     struct hmm_range *range = hmm_vma_walk->range;
0152     unsigned int required_fault;
0153     unsigned long i, npages;
0154     unsigned long *hmm_pfns;
0155
0156     i = (addr - range->start) >> PAGE_SHIFT;
0157     npages = (end - addr) >> PAGE_SHIFT;
0158     hmm_pfns = &range->hmm_pfns[i];
0159     required_fault =
0160         hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0);
0161     if (!walk->vma) {
0162         if (required_fault)
0163             return -EFAULT;
0164         return hmm_pfns_fill(addr, end, range, HMM_PFN_ERROR);
0165     }
0166     if (required_fault)
0167         return hmm_vma_fault(addr, end, required_fault, walk);
0168     return hmm_pfns_fill(addr, end, range, 0);
0169 }
0170
0171 static inline unsigned long hmm_pfn_flags_order(unsigned long order)
0172 {
0173     return order << HMM_PFN_ORDER_SHIFT;
0174 }
0175
0176 static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
0177                          pmd_t pmd)
0178 {
0179     if (pmd_protnone(pmd))
0180         return 0;
0181     return (pmd_write(pmd) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
0182                  HMM_PFN_VALID) |
0183            hmm_pfn_flags_order(PMD_SHIFT - PAGE_SHIFT);
0184 }
0185
0186 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
0187 static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
0188                   unsigned long end, unsigned long hmm_pfns[],
0189                   pmd_t pmd)
0190 {
0191     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0192     struct hmm_range *range = hmm_vma_walk->range;
0193     unsigned long pfn, npages, i;
0194     unsigned int required_fault;
0195     unsigned long cpu_flags;
0196
0197     npages = (end - addr) >> PAGE_SHIFT;
0198     cpu_flags = pmd_to_hmm_pfn_flags(range, pmd);
0199     required_fault =
0200         hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, cpu_flags);
0201     if (required_fault)
0202         return hmm_vma_fault(addr, end, required_fault, walk);
0203
0204     pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
0205     for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
0206         hmm_pfns[i] = pfn | cpu_flags;
0207     return 0;
0208 }
0209 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
0210 /* stub to allow the code below to compile */
0211 int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
0212         unsigned long end, unsigned long hmm_pfns[], pmd_t pmd);
0213 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
0214
0215 static inline unsigned long pte_to_hmm_pfn_flags(struct hmm_range *range,
0216                          pte_t pte)
0217 {
0218     if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte))
0219         return 0;
0220     return pte_write(pte) ? (HMM_PFN_VALID | HMM_PFN_WRITE) : HMM_PFN_VALID;
0221 }
0222
0223 static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
0224                   unsigned long end, pmd_t *pmdp, pte_t *ptep,
0225                   unsigned long *hmm_pfn)
0226 {
0227     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0228     struct hmm_range *range = hmm_vma_walk->range;
0229     unsigned int required_fault;
0230     unsigned long cpu_flags;
0231     pte_t pte = *ptep;
0232     uint64_t pfn_req_flags = *hmm_pfn;
0233
0234     if (pte_none_mostly(pte)) {
0235         required_fault =
0236             hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
0237         if (required_fault)
0238             goto fault;
0239         *hmm_pfn = 0;
0240         return 0;
0241     }
0242
0243     if (!pte_present(pte)) {
0244         swp_entry_t entry = pte_to_swp_entry(pte);
0245
0246         /*
0247          * Don't fault in device private pages owned by the caller,
0248          * just report the PFN.
0249          */
0250         if (is_device_private_entry(entry) &&
0251             pfn_swap_entry_to_page(entry)->pgmap->owner ==
0252             range->dev_private_owner) {
0253             cpu_flags = HMM_PFN_VALID;
0254             if (is_writable_device_private_entry(entry))
0255                 cpu_flags |= HMM_PFN_WRITE;
0256             *hmm_pfn = swp_offset(entry) | cpu_flags;
0257             return 0;
0258         }
0259
0260         required_fault =
0261             hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0);
0262         if (!required_fault) {
0263             *hmm_pfn = 0;
0264             return 0;
0265         }
0266
0267         if (!non_swap_entry(entry))
0268             goto fault;
0269
0270         if (is_device_private_entry(entry))
0271             goto fault;
0272
0273         if (is_device_exclusive_entry(entry))
0274             goto fault;
0275
0276         if (is_migration_entry(entry)) {
0277             pte_unmap(ptep);
0278             hmm_vma_walk->last = addr;
0279             migration_entry_wait(walk->mm, pmdp, addr);
0280             return -EBUSY;
0281         }
0282
0283         /* Report error for everything else */
0284         pte_unmap(ptep);
0285         return -EFAULT;
0286     }
0287
0288     cpu_flags = pte_to_hmm_pfn_flags(range, pte);
0289     required_fault =
0290         hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
0291     if (required_fault)
0292         goto fault;
0293
0294     /*
0295      * Bypass devmap pte such as DAX page when all pfn requested
0296      * flags(pfn_req_flags) are fulfilled.
0297      * Since each architecture defines a struct page for the zero page, just
0298      * fall through and treat it like a normal page.
0299      */
0300     if (!vm_normal_page(walk->vma, addr, pte) &&
0301         !pte_devmap(pte) &&
0302         !is_zero_pfn(pte_pfn(pte))) {
0303         if (hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, 0)) {
0304             pte_unmap(ptep);
0305             return -EFAULT;
0306         }
0307         *hmm_pfn = HMM_PFN_ERROR;
0308         return 0;
0309     }
0310
0311     *hmm_pfn = pte_pfn(pte) | cpu_flags;
0312     return 0;
0313
0314 fault:
0315     pte_unmap(ptep);
0316     /* Fault any virtual address we were asked to fault */
0317     return hmm_vma_fault(addr, end, required_fault, walk);
0318 }
0319
0320 static int hmm_vma_walk_pmd(pmd_t *pmdp,
0321                 unsigned long start,
0322                 unsigned long end,
0323                 struct mm_walk *walk)
0324 {
0325     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0326     struct hmm_range *range = hmm_vma_walk->range;
0327     unsigned long *hmm_pfns =
0328         &range->hmm_pfns[(start - range->start) >> PAGE_SHIFT];
0329     unsigned long npages = (end - start) >> PAGE_SHIFT;
0330     unsigned long addr = start;
0331     pte_t *ptep;
0332     pmd_t pmd;
0333
0334 again:
0335     pmd = READ_ONCE(*pmdp);
0336     if (pmd_none(pmd))
0337         return hmm_vma_walk_hole(start, end, -1, walk);
0338
0339     if (thp_migration_supported() && is_pmd_migration_entry(pmd)) {
0340         if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0)) {
0341             hmm_vma_walk->last = addr;
0342             pmd_migration_entry_wait(walk->mm, pmdp);
0343             return -EBUSY;
0344         }
0345         return hmm_pfns_fill(start, end, range, 0);
0346     }
0347
0348     if (!pmd_present(pmd)) {
0349         if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
0350             return -EFAULT;
0351         return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
0352     }
0353
0354     if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) {
0355         /*
0356          * No need to take pmd_lock here, even if some other thread
0357          * is splitting the huge pmd we will get that event through
0358          * mmu_notifier callback.
0359          *
0360          * So just read pmd value and check again it's a transparent
0361          * huge or device mapping one and compute corresponding pfn
0362          * values.
0363          */
0364         pmd = pmd_read_atomic(pmdp);
0365         barrier();
0366         if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
0367             goto again;
0368
0369         return hmm_vma_handle_pmd(walk, addr, end, hmm_pfns, pmd);
0370     }
0371
0372     /*
0373      * We have handled all the valid cases above ie either none, migration,
0374      * huge or transparent huge. At this point either it is a valid pmd
0375      * entry pointing to pte directory or it is a bad pmd that will not
0376      * recover.
0377      */
0378     if (pmd_bad(pmd)) {
0379         if (hmm_range_need_fault(hmm_vma_walk, hmm_pfns, npages, 0))
0380             return -EFAULT;
0381         return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
0382     }
0383
0384     ptep = pte_offset_map(pmdp, addr);
0385     for (; addr < end; addr += PAGE_SIZE, ptep++, hmm_pfns++) {
0386         int r;
0387
0388         r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, hmm_pfns);
0389         if (r) {
0390             /* hmm_vma_handle_pte() did pte_unmap() */
0391             return r;
0392         }
0393     }
0394     pte_unmap(ptep - 1);
0395     return 0;
0396 }
0397
0398 #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \
0399     defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
0400 static inline unsigned long pud_to_hmm_pfn_flags(struct hmm_range *range,
0401                          pud_t pud)
0402 {
0403     if (!pud_present(pud))
0404         return 0;
0405     return (pud_write(pud) ? (HMM_PFN_VALID | HMM_PFN_WRITE) :
0406                  HMM_PFN_VALID) |
0407            hmm_pfn_flags_order(PUD_SHIFT - PAGE_SHIFT);
0408 }
0409
0410 static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
0411         struct mm_walk *walk)
0412 {
0413     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0414     struct hmm_range *range = hmm_vma_walk->range;
0415     unsigned long addr = start;
0416     pud_t pud;
0417     spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma);
0418
0419     if (!ptl)
0420         return 0;
0421
0422     /* Normally we don't want to split the huge page */
0423     walk->action = ACTION_CONTINUE;
0424
0425     pud = READ_ONCE(*pudp);
0426     if (pud_none(pud)) {
0427         spin_unlock(ptl);
0428         return hmm_vma_walk_hole(start, end, -1, walk);
0429     }
0430
0431     if (pud_huge(pud) && pud_devmap(pud)) {
0432         unsigned long i, npages, pfn;
0433         unsigned int required_fault;
0434         unsigned long *hmm_pfns;
0435         unsigned long cpu_flags;
0436
0437         if (!pud_present(pud)) {
0438             spin_unlock(ptl);
0439             return hmm_vma_walk_hole(start, end, -1, walk);
0440         }
0441
0442         i = (addr - range->start) >> PAGE_SHIFT;
0443         npages = (end - addr) >> PAGE_SHIFT;
0444         hmm_pfns = &range->hmm_pfns[i];
0445
0446         cpu_flags = pud_to_hmm_pfn_flags(range, pud);
0447         required_fault = hmm_range_need_fault(hmm_vma_walk, hmm_pfns,
0448                               npages, cpu_flags);
0449         if (required_fault) {
0450             spin_unlock(ptl);
0451             return hmm_vma_fault(addr, end, required_fault, walk);
0452         }
0453
0454         pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
0455         for (i = 0; i < npages; ++i, ++pfn)
0456             hmm_pfns[i] = pfn | cpu_flags;
0457         goto out_unlock;
0458     }
0459
0460     /* Ask for the PUD to be split */
0461     walk->action = ACTION_SUBTREE;
0462
0463 out_unlock:
0464     spin_unlock(ptl);
0465     return 0;
0466 }
0467 #else
0468 #define hmm_vma_walk_pud    NULL
0469 #endif
0470
0471 #ifdef CONFIG_HUGETLB_PAGE
0472 static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask,
0473                       unsigned long start, unsigned long end,
0474                       struct mm_walk *walk)
0475 {
0476     unsigned long addr = start, i, pfn;
0477     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0478     struct hmm_range *range = hmm_vma_walk->range;
0479     struct vm_area_struct *vma = walk->vma;
0480     unsigned int required_fault;
0481     unsigned long pfn_req_flags;
0482     unsigned long cpu_flags;
0483     spinlock_t *ptl;
0484     pte_t entry;
0485
0486     ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte);
0487     entry = huge_ptep_get(pte);
0488
0489     i = (start - range->start) >> PAGE_SHIFT;
0490     pfn_req_flags = range->hmm_pfns[i];
0491     cpu_flags = pte_to_hmm_pfn_flags(range, entry) |
0492             hmm_pfn_flags_order(huge_page_order(hstate_vma(vma)));
0493     required_fault =
0494         hmm_pte_need_fault(hmm_vma_walk, pfn_req_flags, cpu_flags);
0495     if (required_fault) {
0496         spin_unlock(ptl);
0497         return hmm_vma_fault(addr, end, required_fault, walk);
0498     }
0499
0500     pfn = pte_pfn(entry) + ((start & ~hmask) >> PAGE_SHIFT);
0501     for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
0502         range->hmm_pfns[i] = pfn | cpu_flags;
0503
0504     spin_unlock(ptl);
0505     return 0;
0506 }
0507 #else
0508 #define hmm_vma_walk_hugetlb_entry NULL
0509 #endif /* CONFIG_HUGETLB_PAGE */
0510
0511 static int hmm_vma_walk_test(unsigned long start, unsigned long end,
0512                  struct mm_walk *walk)
0513 {
0514     struct hmm_vma_walk *hmm_vma_walk = walk->private;
0515     struct hmm_range *range = hmm_vma_walk->range;
0516     struct vm_area_struct *vma = walk->vma;
0517
0518     if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)) &&
0519         vma->vm_flags & VM_READ)
0520         return 0;
0521
0522     /*
0523      * vma ranges that don't have struct page backing them or map I/O
0524      * devices directly cannot be handled by hmm_range_fault().
0525      *
0526      * If the vma does not allow read access, then assume that it does not
0527      * allow write access either. HMM does not support architectures that
0528      * allow write without read.
0529      *
0530      * If a fault is requested for an unsupported range then it is a hard
0531      * failure.
0532      */
0533     if (hmm_range_need_fault(hmm_vma_walk,
0534                  range->hmm_pfns +
0535                      ((start - range->start) >> PAGE_SHIFT),
0536                  (end - start) >> PAGE_SHIFT, 0))
0537         return -EFAULT;
0538
0539     hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);
0540
0541     /* Skip this vma and continue processing the next vma. */
0542     return 1;
0543 }
0544
0545 static const struct mm_walk_ops hmm_walk_ops = {
0546     .pud_entry  = hmm_vma_walk_pud,
0547     .pmd_entry  = hmm_vma_walk_pmd,
0548     .pte_hole   = hmm_vma_walk_hole,
0549     .hugetlb_entry  = hmm_vma_walk_hugetlb_entry,
0550     .test_walk  = hmm_vma_walk_test,
0551 };
0552
0553 /**
0554  * hmm_range_fault - try to fault some address in a virtual address range
0555  * @range:  argument structure
0556  *
0557  * Returns 0 on success or one of the following error codes:
0558  *
0559  * -EINVAL: Invalid arguments or mm or virtual address is in an invalid vma
0560  *      (e.g., device file vma).
0561  * -ENOMEM: Out of memory.
0562  * -EPERM:  Invalid permission (e.g., asking for write and range is read
0563  *      only).
0564  * -EBUSY:  The range has been invalidated and the caller needs to wait for
0565  *      the invalidation to finish.
0566  * -EFAULT:     A page was requested to be valid and could not be made valid
0567  *              ie it has no backing VMA or it is illegal to access
0568  *
0569  * This is similar to get_user_pages(), except that it can read the page tables
0570  * without mutating them (ie causing faults).
0571  */
0572 int hmm_range_fault(struct hmm_range *range)
0573 {
0574     struct hmm_vma_walk hmm_vma_walk = {
0575         .range = range,
0576         .last = range->start,
0577     };
0578     struct mm_struct *mm = range->notifier->mm;
0579     int ret;
0580
0581     mmap_assert_locked(mm);
0582
0583     do {
0584         /* If range is no longer valid force retry. */
0585         if (mmu_interval_check_retry(range->notifier,
0586                          range->notifier_seq))
0587             return -EBUSY;
0588         ret = walk_page_range(mm, hmm_vma_walk.last, range->end,
0589                       &hmm_walk_ops, &hmm_vma_walk);
0590         /*
0591          * When -EBUSY is returned the loop restarts with
0592          * hmm_vma_walk.last set to an address that has not been stored
0593          * in pfns. All entries < last in the pfn array are set to their
0594          * output, and all >= are still at their input values.
0595          */
0596     } while (ret == -EBUSY);
0597     return ret;
0598 }
0599 EXPORT_SYMBOL(hmm_range_fault);